Conventional metal-oxide-based gas sensors are used for the detection and quantification of various gases. These sensors typically require temperatures of up to 400° C. in order to function. In a MEMS embodiment, such sensors are often implemented with a silicon dioxide or silicon nitride diaphragm on which a heating element made of platinum or other materials is disposed. Reliability in this context is problematic, especially in conjunction with miniaturization of the sensors for use in mobile user devices such as smartphones.
In this connection, electromigration can represent a particularly relevant damage mechanism that can lead to rapid failure of the aforesaid heating structures as a result of design weaknesses. Miniaturization of the sensors and correspondingly of the conductor paths generally results in a higher current density and can aggravate the problems even more.
U.S. Pat. No. 6,450,025 B1 describes a micro-heating element having a layer structure with which distortion or warping of the micro-heating element can be limited.
U.S. Pat. No. 8,410,560 B2 describes a micro-heating plate with bidirectional current flow in order to reduce electromigration.